I was wondering how a tire size such as a 205/40/17 are translated into. I know that the 17 stands for 17 inches, but how do the other numbers measure up?

97 RS in Union City CA
Mods: Injen Intake, 1.3" drop

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For a tire size of, let's say, 205/55R16, here's the explanation

The 205 means the tread of the tire is 205 mm wide

The 55 means the sidewall is 55% as tall as the tread is wide (so a 205/55 tire is 205 mm wide and about 112 mm tall)

Of course, there is the speed rating, the load rating, the traction rating, the temperature rating and the treadwear rating, but that's another post :)

Todd Scungio
98 RS
15.803 @ 86.48 MPH